what you didn't know about structural steel

What You Don’t Know About Structural Steel

Structural steel beams form the backbone of many construction projects. But what is structural steel and how is it used?

Many people don’t know that structural steel is not one single alloy. Different concentrations of alloying elements are added to accomplish different objectives. Here are some of the most commonly found structural steel alloys:

Cold Rolled ASTM-A1008 is a low carbon steel material that comes in formed shapes such as channel and angle, for general structural applications. The additional steps for cold rolling give the steel a finer finish and improved dimensional accuracy.

Hot rolled (HR) ASTM-A36 mild (low-carbon) steel contains up to 27% carbon – more than standard mild steel. It has a minimum yield point of 36K, and is easily weldable and formable. It is one of the most widely used structural steels in a range of applications, including support frames, machinery and equipment braces, and transportation frames. HR A36 is also available in Galvanized form, for added corrosion resistance.

Hot rolled (HR) ASTM-A529 Grade 50 steel is stronger than A36, meeting the standard of 50K minimum yield strength. This steel is used for supports and structural components in bridges, buildings and other structures requiring increased strength. It can be welded, bolted, riveted, machined and fabricated easily.

Structural Cross Sections

Structural steel comes in different cross sections, including channel, angle, beam, and tee. These cross sectional shapes can either be formed or welded. Because they’re available in a huge variety of sizes and styles, steel structural shapes are used to build everything from furniture to skyscrapers. Common applications include:

  • Marine piers
  • Architecture & building construction
  • Shipbuilding
  • Truck trailers & shipping containers
  • Furniture
  • Heavy equipment
  • and more

Steel Angle Shape

Angle – Steel angle is available in different grades, including Cold Rolled ASTM A-1008, Hot Rolled ASTM-A36 Steel Angle, and Galvanized A36. Steel angle is used for a wide range of applications, including construction equipment, farm implements, manufacturing and repair, and fabrication. Its 90° angled shape adds an abundance of strength and rigidity to numerous projects and it is easy to weld, cut, form and machine.

Tee Shape

Tee – The “T” shape of hot rolled steel tee makes it favorable for applications where large loading bearing capabilities are a must, including fabrication, manufacturing, frames, trailers, etc. The top (flange) provides compressive stress resistance while the vertical section (web) resists shear stresses and bending. This product is also easy to weld, cut, form and machine.

Channel Shape

Channel – Steel channel can be constructed with cold rolled mild steel, hot rolled mild steel or hot rolled ASTM-A36 steel alloy. The interior may be fabricated with radius corners or 90° angled corners. Hot rolled steel channel has a mild steel structural C shape with inside radius corners that are ideal for all types of structural applications. The shape of this product is also ideal for added strength and rigidity over steel angle when a project’s load is vertical or horizontal, and can be easily welded, cut, formed and machined.

Beam Shape

Beam – Hot rolled steel I-beams provide great load bearing support when used horizontally or standing as columns. They are also used regularly throughout the construction industry when heavy load support is required, such as bridges and skyscrapers.

Industrial Metal Supply offers a full line of durable, long-lasting, and versatile structural steel shapes, including steel channel, steel angle, steel beams, and steel tees, a range of standard sizes and lengths. We also provide cut-to-length services as needed to give you steel shapes that match your design requirements.


Tips to Advance Welding Skills

7 Tips to Advance your Welding Skills

Whatever your project – whether mending a metal fence or repairing teeth on a backhoe bucket, the following advanced welding tips will help you get the job done faster, and with less waste and effort.

1. Make Good Use of Magnets

Choose from a wide range of specialized magnets or clamps to use as “third hands.” These can securely hold welding tabs, brackets or gussets to the workpiece, lids on a box, or corners perpendicular during the welding process. Use an adjustable welding table to support smaller items. Don’t remove magnets until the weld has completely cooled, so that the hot metal doesn’t shrink and ruin the alignment.

2. Welding Out of Position

If you can’t fix your workpiece in a comfortable, flat welding position using magnets and clamps, it’s important to remember that the weld puddle may drip. If welding overhead, move quickly and steadily using a circular motion but keep the puddle narrow. To allow the puddle to cool faster, maintain a lower electrode temperature by reversing polarity, and use less voltage so that the puddle remains small.

3. Completely Clean Out the Area to Be Repaired

Impurities such as oil, grease, dust, and moisture, can cause problems later if they are absorbed into the metal. Clean out the area thoroughly using a sander or wire brush and wipe away any debris. If repairing cracks, grind them out with a grinder before welding. Where the shape and size of the crack make it impossible to reach the bottom, use a slower welding speed, which allows time for impurities, such as hydrogen bubbles, to rise to the surface before they become trapped.

4. Beware of Hydrogen

Hydrogen is the enemy, when it comes to welding. Certain metals, such as high-strength steel, are more susceptible to hydrogen cracking, which may occur long after the weld is completed. Welding thick or highly restrained pieces can also cause cracking. Before welding, seek and destroy any alien material, such as paint, dust, or grease. Then preheat the metal before, during, and even after welding for a few hours. This slows down the cooling time so that more hydrogen can escape before the metal solidifies.

5. Bead-Laying Tips

With stick welding, it’s important to run a straight bead by keeping an even travel speed – and maintain the angle of the rod so that the slag trails behind. When you get to the end of the weld, run the rod back in the other direction an inch or so, in order to prevent a crater developing that could crack later.

6. Choose the Best Electrode for the Job

For general use stick welding, choose a 6011 electrode, but for thinner material, go with a 6013. Rod diameter should be higher for thicker metal and smaller for thinner stock.

In the case of high-carbon or other high-alloy steels that are harder to weld, it’s important to use low-hydrogen electrodes. Be sure to leave them in the package until the last minute, to expose them to air for as short a time as possible.

7. Be Aware of Aluminum Welding Differences

When welding aluminum, different materials and techniques are required. Aluminum should be welded with either a TIG or MIG process. Before welding, remove oxides from the aluminum surface using a stainless steel brush and solvents. These oxides have a very high melting temperature, which can inhibit the filler from welding with the metal. Use only argon-helium or argon gas to shield the weld. Preheat the area, but don’t overheat, which could cause burn-through. At the end of the weld, don’t leave a crater, which will inevitably lead to cracking. Instead back weld for an inch or so.

For all your welding supplies, including tools, consumables, and accessories, visit Industrial Metal Supply.